public class useSuper{
    public static void main(String[] args) {
        Son s = new Son();
        s.method();
        System.out.println("==========");
        Base s2 = new Son();
        s2.method();
        System.out.println("=========");
        s.sonMethod();

        Base base = s;
        s = (Son)base;
        if(base instanceof Son) {
            base.prfMumber();
        }
    }
}

